August 27, 2017 to September 1, 2017
RAI Congress Center, Amsterdam, The Netherlands
Europe/Amsterdam timezone

Design of a dipole with longitudinally variable field using permanent magnets for CLIC damping rings

Aug 30, 2017, 11:00 AM
G102-103 Room

G102-103 Room

Regular 15 minutes Oral Presentation A2 - Resistive Accelerator Magnets Wed-Mo-Or19


Fernando Toral (Centro de Investigaciones Energéti cas Medioambientales y Tecno) Manuel Angel Dominguez Martinez (Ciemat)


The latest CLIC damping ring lattice is based on magnets with longitudinally variable dipole fields in order to achieve ultra-low beam emittance, while keeping the ring circumference small. These magnets need to provide a focusing gradient of 11 T/m as well. The good field region radius is 5 mm. The field harmonics shall be in the order of 1E-4 of the main one. Since only a small variation of the field is requested, permanent magnets are the most cost-effective solution. Beam dynamics calculations have provided idealized field profiles and magnetic calculations have been performed to check their feasibility. FEM electromagnetic computations are complicated because the cross-section of the magnet is not constant. Therefore, iron poles cannot be modeled by extrusion and only 3-D computations are meaningful. Mechanical calculations have been also realized to evaluate the forces and design the support structure. Finally, this paper shows that small variations of field strength are possible by using moving parts.

Submitters Country Spain

Primary author


Fernando Toral (Centro de Investigaciones Energéti cas Medioambientales y Tecno) Dr Hossein Ghasem (IPM - Institute for Research in Fundamental Sciences (IR)) Parthena Stefania Papadopoulou (University of Crete (GR)) Yannis Papaphilippou (CERN)

Presentation materials